Patent GB-827020-A (GB)
Title: Improvements in or relating to type printing telegraph apparatus
IPC: H04L13/18
Filed: 1957-05-17
Abstract: 827,020. Type-printing telegraphy. CREED & CO. Ltd. May 17, 1957 [May 23, 1956], No. 15790/57. Class 40 (3). In an arrangement for preventing overprinting at the end of a line of print by a distant page-printer operated by a keyboard transmitter provided with a tape-printer and perforator and including a counting mechanism which provides a warning signal towards the end of a line and operates to lock the keys of the keyboard when a predetermined number of signals has been counted, the function signals, such-as figure-shift, lettershift, bell, line-feed ... , which do not involve character spacing, are not counted, and the counting mechanism can be adjusted to vary the number of characters counted to control the warning and keyboard-locking functions. When a transmitted character involves spacing at the distant or connected receiver the bar 4 is moved to the right by the operated key lever 6 and the projection 4a moves against the lever 9. At the same time a cam 13 on the transmitter shaft 12 rocks a lever 14 which through arms 15, 17 on a spindle 16 actuates a pawl 11 engaging a ratchet-wheel 18 on a counter device 20 which is held in its stepped position by a retaining pawl 21. On the operation of a key 6 pertaining to a function signal not requiring letter-spacing, such as figure-shift, letter-shift, line feed, bell, &c. the bar 3 is moved to the left and its projection 3a engages the arm 9 which in conjunction with the abutment plate 10 rocks the pawl 11 out of engagement with the ratchet 18 so that the rotation of the cam 13 is ineffective to step the counter 20. Towards the end of a line, e.g. 10 characters from the end, the end of a pivoted lever 22 falls into a recess 19a of a disc 19 secured by a screw-and-slot to the ratchet 18 and operates a switch mechanism 29 to illuminate a coloured light near the keyboard to warn the operator that the carriage-return signal should be sent after a further limited number of characters. When the number of characters for a complete line has been counted the end of a lever 23 drops into the slot 19a and moves to the right a bar 7 having a recessed portion 7a allowing a bar 2 to move to the left so that projections 2c block all key levers 6 except that assigned to the carriage-return signal. When this lever 6 is operated, the bar 3 moves to the left so that the projection 3a disengages the pawl 11 from the ratchet 18, and projections 5a, 5b on the bar 5 which is moved to the right, rock the levers 22, 23 out of engagement with the recess 19a. The retaining pawl 21 rocked out of engagement with the ratchet 18 by the projection 5c is held by latch member 30 so that the counting device 20 returns under the action of spring 25 to its normal position in which a locating arm 26 unlatches member 30 and is held against a stop 27. The bar 2 is moved to the right so that the keyboard is unlocked and the lever 7 is returned by spring 28 to its normal position with the shouldered portion 7a against the projection 2a. The ratchet 18 is rotatively adjustable relative to the recessed disc 19 by means of the slot 31 and screw 32 so that the functions of the apparatus may be performed for lines of print having different numbers of characters, i.e. according to width of sheet employed by the distant page-printer.